Where it is certified to the Chief Executive Officer by a medical practitioner that the outbreak or spread of any infectious or contagious disease in the cantonment is, in the opinion of such medical practitioner, attributable to the milk supplied by any dairyman, the Chief Executive Officer may, by notice in writing, require the dairyman, with in such time as may be specified in the notice, to furnish him with a full and complete list of the names and addresses of all his customers within the cantonment, or to give him such information as will enable him to trace the persons to whom the dairyman has sold milk.